Add option to demonstrate persistent service

I suggest that the example have an option to show running a service as a persistent one so it doesn't stop on app close.

It could be a check box that says "run as persistent service"

I've tried to make it an auto restart service with this line in `start_service` function:

```python
service.mService.setAutoRestartService(True)
```
but no luck.

Start by locating the example's `start_service` function and inspect how `service.mService` is created and stopped when the app closes. Determine how the proposed checkbox should control persistent behavior, then verify that the service remains running after app closure and that the default behavior is unchanged.

Written by the indexing model from the issue text.